Synthesis of N-aryl and N-heteroaryl hydroxylamines via partial reduction of nitroarenes with soluble nanoparticle catalysts
Polystyrene-supported ruthenium nanoparticles enable the selective hydrazine-mediated reduction of nitroarenes to hydroxylamine products in high yield and selectivity. Key to obtaining the hydroxylamine product in good yield was the use of organic solvents capable of solubilizing the polystyrene-supported nanoparticle catalyst. N-aryl and N-heteroaryl hydroxylamines are generated under exceptionally mild conditions and in the presence of a various easily reduced functional groups.
Tyler, Jefferson H.,Nazari, S. Hadi,Patterson, Robert H.,Udumula, Venkatareddy,Smith, Stacey J.,Michaelis, David J.
p. 82 - 86
(2016/12/23)
Thiophenes as traps for benzyne. 3. Diaryl sulfides and the role of dipolar intermediates
The reactions of seven thiophenes with benzyne generated from diphenyliodonium-2-carboxylate (DPIC) under a standard set of conditions led among other products to the formation of α- and β-naphthyl phenyl sulfides 2a and 2b from thiophene (1a) and of 2c: and 2d from 2-methylthiophene (1b). Dithienyl sulfides 4a-f were produced from the halothiophenes 1c-g. The structures of the naphthyl sulfides were proven by comparison with authentic samples of 2a-f, thus eliminating one of two possible mechanisms of formation. The remaining mechanism involves [4+2]-cycloaddition of benzyne to thiophene or to an S-phenylthiophenium ylide 10 to give the dipolar 2:1 benzyne/thiophene adduct 8 followed by ring-opening. Stevens-like rearrangements of 11, formed from 10 by proton transfer, may also explain the origin of arylated thiophenes such as 12 and 3 found in some reactions of benzynes with thiophene.
Reinecke, Manfred G.,Del Mazza, Dario,Obeng, Marcus
p. 70 - 74
(2007/10/03)
ONE-POT CHEMOSELECTIVE REDUCTIVE ALKYLATION OF NITROARENES: A NEW GENERAL METHOD OF SYNTHESIS OF ALKYLANILINES.
A New facile and general synthesis of alkylanilines by one-pot reductive alkylation of nitroarenes is reported.This method is based on the "in situ" reduction by hydrides (LiAlH4 or NaBH4) in the presence of catalytic amounts of Pd/C, of nitronate adducts arising from the conjugate addition of Grignard reagents to mononitroarenes.LiAlH4 showed to be a more efficient but less selective reducing agent than NaBH4.The reaction can be successfully applied to mono, homo and hetero bicyclic systems and allows to introduce a large variety of alkyl chains without isomerisation phenomena.
Aromatic amines (e.g., aniline) are selectively alkylated in an ortho nuclear position by reaction with an olefin (e.g., ethylene) in the presence of an aluminum anilide catalyst. Hydrogen halides (e.g., HCl) are added to increase the reaction rate.
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(2008/06/13)
Reaction of N-haloamide. XXVIII. Preparation of N,N-dibromourethan and reactions of N,N-dihaloamides with styrene and 1,2-dihydronaphthalenes